1. Field of the Invention
The present invention relates in general to frequency standards and frequency measuring devices.
2. Description of the Prior Art
The dissemination and use of frequency standards is extremely important to many of the activities of everyday living. For example, radio and television stations and navigators of ships and airplanes require precise, constantly available and internationally recognized frequency standards for proper regulation of their equipment. In the United States, the National Bureau of Standards broadcasts continuous signals at standard frequencies from its high-frequency radio station WWV.
To effectively utilize such radiated radio frequency standard signals, need has arisen for practical, reliable and relatively inexpensive devices for generating signals at useable strength levels and at frequencies which are directly related to those of the standard signals. The strength of a typical received radio frequency signal is in the micro-volt range; in order to use this low-level signal, it must be amplified to a value on the order of 0.25 volts, a much higher voltage level. In the use of conventional amplification techniques, it has been found that undesirable feedback frequently causes oscillation, thereby preventing reception and use of the received radio frequency signal.